QtWidgets.QApplication.translate syntax error using PySide

[elveatles]

The translate method is different between Qt4 and Qt5.
You can try this Python code:

import sys

from Qt import QtWidgets

class MainWindow(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        title = QtWidgets.QApplication.translate("MainWindow", "MainWindow", None, -1)

def main():
    app = QtWidgets.QApplication(sys.argv)
    mainWindow = MainWindow()
    mainWindow.show()
    app.exec_()

if __name__ == '__main__':
    main()

If I have PySide2, this will work. If I have PySide, I will get the error:

TypeError: 'PySide.QtCore.QCoreApplication.translate' called with wrong argument types:
PySide.QtCore.QCoreApplication.translate(str, str, NoneType, int)
Supported signatures:
PySide.QtCore.QCoreApplication.translate(str, str, str = None, PySide.QtCore.QCoreApplication.Encoding = CodecForTr)
PySide.QtCore.QCoreApplication.translate(str, str, str, PySide.QtCore.QCoreApplication.Encoding, int)

I was trying to compile .ui files like how it is being done in #88 compiling resources . And this always generates a bunch of translate lines.

[mottosso]

Thanks for reporting this @elveatles.

This is an area where I'm open to suggestions. It seems to me that the problem is compiling for a particular binding, and then attempting to run it on another. Does that sound about right?

One way to solve this might be to monkey patch the QCoreApplication.translate function. But the problem with this is that it breaks rule 3; co-existence with original bindings. That is, it may break non-Qt.py programs in subtle and unexpected ways.

I wonder whether a more cross-compatible way to handle this is first to compile the ui file into a py file, and perform some kind of post operation on it via Qt.py.

$ compile_ui my_widget.ui
$ Qt.py --convert my_widget.py

The post operation could replace the translate function with whatever it is expected to produce using some function that works across every binding.

Alternatively, if it's possible to somehow get to the generated code from the loadUi function and friends, and modify it before it executes.

Let me know what you think.

[elveatles]

For my own code, I ended up monkey patching the translate function. Even though it hasn't caused me problems yet, I am worried about unforeseen consequences.

I do like the idea of using Qt.py --convert my_widget.py. Currently, I'm compiling with pyside2uic and then simply doing a replace(u'PySide2', u'Qt') on the compiled .py file. I find this a lot easier than trying to convert my existing code from using setupUi to loadUi.

Thanks for looking into this.

[mottosso]

Currently, I'm compiling with pyside2uic and then simply doing a replace(u'PySide2', u'Qt') on the compiled .py file.

That may be all there is to it.

Qt.py is all about PySide2 compatibility, so whatever pyside2uic throws at it, it should be able to handle.

Do you think it would make sense to make this the only supported method of working with .ui files? Even for those working with PyQt4, or even PyQt5? That they (1) perform a conversion to .py, and (2) another conversion from PySide2 to Qt.py?

I know some prefer the in-memory method of load_ui(). Do you think there is any way of wrapping pyside2uic up in such a way that it acts like load_ui(), but runs through (1) and (2) implicitly?

[elveatles]

I think the choice of whether to compile .ui files or use load_ui should be left to the user since Qt bindings give you that choice as well.

[mottosso]

I think the choice of whether to compile .ui files or use load_ui should be left to the user since Qt bindings give you that choice as well.

Agreed. Do you think it's reasonable to have Qt.py encourage compiling .ui files via pyside2uic, even for users working with other bindings?

That way, we can setup a "Compiling ui files with Qt.py" guide which would essentially be a PySide2 guide, with the added post-conversion to Qt.py.

[elveatles]

Yes, I think it would be great to have a compiling guide plus a post-conversion script. Since Qt.py does things the PySide2 way, it makes sense to use pyside2uic.

[mottosso]

Hi @elveatles, let me know if this works for you.

• https://github.com/mottosso/Qt.py/releases/tag/0.5.0